Manufacture of paper



MANUFACTURE OF PAPER Filed May 10, 1932 gfiwib ('5 W.

' INVENTOR ATTORNEY Patented June 20, 1933 UNITED STATES PATENT OFFICEGEORGE L. B IDWELL, OF RIEGELSVILLE, PENNSYLVANIA, ASSIGNOR TO RiEG-ELPAPER CORPORATION, OF RIEGELSVILLE, NEW JERSEY, A CORPORATION OF NEWJERSEY MANUFACTURE or PAPER Application filed May 10,

This invention relates to paper making, and more particularly to themanufacture of paper, such as glassine, imitation parchment, and thelike, from stock of highly gelatinized fibers; and the object thereof isboth .to improve and control the quality and other desirablecharacteristics of paper of this type.

In the standard fourdrinier paper making machine, the paper stock iscaused to flow on the fourdrinier wire where the web is formed and aportion of the water is eX- tracted therefrom first by capillaryattraction as the web passes over tube rolls and then by suction as itpasses over the usual fiat suction boxes and the final suction couchroll. From the fourdrinier wire the web is conducted, upon one or more,usually three, endless felt carriers, first between lower suction andtop press rolls and then between one or more pairs of standard pressrolls by which more water is mechanically pressed from the web. Onleaving the last of these rolls the web passes over and around apreliminary pair of smoothing rolls and then over and around an extendedbattery of steam drying cylinders, which serve to evaporate out most ofthe water contained therein. If the paper is to be sized the usual sizepress is inserted atthe end of the battery of drying cylinders and a.few more drying cylinders are added to remove some. or all of themoisture taken up by the paper web from the size press, the number ofthe extra cylinders used depending upon the grade of the paper to bemade. The paper web or sheet, thus'dried, is then fed through a pair ofcalender rolls and wound up into rolls uponreels; and as each roll ofpaper is completed the reel is removed and set in bearings Qua frame andthe paper is unrolled and. run through a slitting and winding machine.-The imitation parchment is a finished product at this stage, but, inthe case of glassine, the paper requires further treatment whichconsists in dampening it,

and, usually, running it through a waxing in the surface of the sheet.

1932. Serial No. 610,506.

qualities of glassine and imitation parchment papers because the stockis so highly gelatinized that the paper web is very reluctant to give upits water as it is carried on the fourdrinier Wire over the tube rolls,suction boxes and suction couch roll. The surface of the sheet,therefore, receives a very distinct wire mark, and, further, the nap onthe felts becomes ,pasty because sufiicient water has not been removedfrom the highly gelatinized stock by the wire to allow the woolen feltsto remove water at the press rolls Without leaving felt marks in thesurface of the paper; and both wire marks and felt marks leave a whitefield in glassine paper ,when it is supercalendered, thereby giving it amore or less opaque characterissible to carry the hydration of fibersfor these papers to almost a state of gelatin without the production ofeither wire or felt marks The very wet paper is so dried as it passesover the suction boxes and between the suction couch. and upper pressrolls of this second wire that when it is transferred to the woolen feltthe nap of the felt will not become pastyland the press-rolls willremove considerable water,

and ohfthe last woolen felt the press rolls will remove more waterwithout crushing or marking the surface of the sheet.

A second feature of the invention consists in impregnating the sheetafter; it has been partially dried but while still holding aconsiderable percentage of moisture, as by suitably dividing the batterof'drying cylinders into two sections an. passing the sheet through abath in a size-press installed be-' sheen and the plasticizer serves togive the paper pliability and more or less stretch and, in the case ofmagnesium or zinc chloride, also adds to the weight of the sheet, and byvarying the proportions of these ingredients and by diluting thesolution with more or less water, I can control the degree of thesevarious characteristics in the finished paper.

Another feature, which relates to the final steps in the manufacture ofglassine paper and which enhances both its transparency and glossysurface, consists in a thorough and even dampening of the paper effectedby running it through a mechanical dampener .which throws a fine sprayofwater, preferably alkali treated as by dissolving therein approximately2 to 5 per cent. of sodium meta-silicate or its equivalent, against itsunder side and further spraying it with. an air-operated atomizer,brushing the sprayed .water evenly into the paper, and then winding itup tightly into a roll. Both surfaces of the sheet are thus so softenedthat when it is run through the supercalenders it takes on a very highgloss and becomes exceedingly transparent.

The invention also comprises the other novel features hereinafterdescribed and specifically pointed out in the appended claims.

The invention will be understood by reference to the accompanyingdrawing the single figure of which is a broken view showing,diagrammatically and with some of the usual parts omitted, a standardfourdrinier paper machine as modified by the improvements by which Ieffect and control the desiredcharacteristics of glassine and/ orimitation parch mentpaper made thereon.

As herein illustrated, 2 indicates an end of the usual fourdrinierendless wire cloth, on which the paper web 1 (indicated throughout byaline'of dashes) is formed, and 3 is the suction couch .roll with whichthis end of the wire is equipped. The second or additional fourdrinierendless wire cloth 4, which as statedis either inserted immediatelybefore or in place of the first of the usual end.- less felts, isequipped with flat suction boxes 5 and a suction couch roll 6 and toppress roll 7. 8 is an endless felt, only one of which is shown, and isequipped with the usual pair I of press rolls 9. The drying cylinders 10are those of .the first of the two sections into which the battery ofdryers is divided. The size-press, installed between the two sections ofthe drying battery, comprises a pan 11, in which is placed the solutionwith which I at this stage impregnate the paper web to improve andcontrol the characteristics of the paper, and two rolls 12 the lower ofwhich rotates in the pan to pick up from the bath a film of the solutionand transfer it to the under side of the paper web. The drying cylinders13 constitute the second of the twosections of the drying battery, andthe rolls 14 are two cooling rolls contacting each with an opposite sideof the sheet of paper. On leaving the cooling rolls, the paper Web ornow dried sheet is wound into rolls upon reels, ordinarily a reel whichis mounted in standards and when filled is removed therefrom andtransferred to a standard slitting and winding machine, but here asshown upon one of a plurality of similar reels 15 mounted upon arotatable frame 16, which, as one reel is filled, is revolved so tocarry that reel forward into an unwinding position and bring=a secondreel down into winding position, where it is connectedby any suitableclutch'mechanism to a driven member. to unwinding position, the paper iscarried through a mechanical dampener 17, comprising a revolving brush18 geared to a driven brass roll 19 rotating in a pan 20 of water,

. preferably alkali treated as stated, the roll picking up a film of thewater which the brush throws in'a fine spray against the under side ofthe paper, and thence over an air-operated atomizer 21, used in combinattion with the mechanical dampener, which throws an exceedingly uniformmist of water,

also preferably alkali treated, over the under side of the sheet justbefore it passes to and is slit and trimmed to proper width in a slitterand winder 22. The slitter and winder, as shown, comprises ascore-cutting slitter' 23 working against a case-hardened drum 24, tworevolving drums 25 supporting a shaft 26, upon which the paper istightly wound on the drum principle, the roll of paper as formed uponthe shaft resting'upon and being rotated by the drums, and anoscillating brush 27 of the coating type which thoroughly brushes thesprayed water into the paper, and evenly over and intimately in contactwith all the gelatinous fibers that-make up the sheet, and asthe roll ofpaper is wound up tightly on the shaft, supported by the revolvingdrums, the wet side of the sheet dampens theother side by its contacttherewith. I

In the operationof the paper machine modified as illustrated and"described it is possible, as stated, to carry the hydration of thefibers'to almost a state of gelatin and yet sufficient water willberemoved from the very wet web in its passage over-the second F romafilled reel, when shifted fourdrinier wire to enable it to be handled onthe felts Without leaving either wire or felt marks in its surface.

For the impregnating bath I now prefer, and recommend, cerelose as thematerial for improving what may be termed the visual characteristics ofthe paper andglycerin as the plastici'zer to give it pliability andstretch, and I have obtained highly satisfactory results both from asolution composed approximately of 4 per cent. sodium meta-silicate,

per cent. cerelose, 20 per cent. glycerin, and 56 per cent. water or of4: per cent. sodium meta-silicate, per cent. cerelose, 20 per cent.glycerin, and 36 per cent. Water.

, A. still more plastic sheetis obtained by the it in the size-press aswell as in the dampeners.

Attempts have been made to impregnate the paper with this solution bothbefore it reaches and after leaving the drying cylinders. Such attempts,however, have proven unsatisfactory and uncommercial.

For example, if the paper web is passed through the solution when nearlydry it-will take up large quantities thereof and the excess will have tobe dried out again. I have found that decidedly the best results-areobtained by bringing the paper web to the first section of the dryingbattery with a moisture content of approximately 82 per cent to 18 percent of fiber and to so divide the battery that the cylinders in thefirst section will remove about 14 to 20 of such 82 per cent.

.moisture content, leaving the sheet with some to 68 per cent. ofmoisture at the time it passes through the impregnating bath in thesize-press. The sheet will then lose all except approximately 5 percent. of its mo1sture in passing through the second sectlon of thedrying battery and this moisture content will be increased toapproximately 7 per cent. by the action of the cooling rolls before thesheet is reeled. The ordinary size press and extra drying cylinders, ifused, should be inserted between the second section of the dryingbattery and the cooling rolls.

Glassine paper when thus treated and afterwards thoroughly and evenlydampened by the combined spraying, atomizing and brushing described,especially where the I water used is alkali treated, takes on a veryhigh gloss and becomes exceedingly transparent on passing through thesuper-calenders and these qualities are further enhanched when the paperis put through a waxing machine using a wax of high temperature. i

It will of course be understood that the invention can be modified inits various details, within the scope of the appended claims, withoutdeparting from the spirit or sacrificing the substantial advantagesthereof.

What I claim as new, and desire to secure by Letters Patent, is v 1. Theprocess of manufacturing paper free from wire and felt marks from highlygelatinized stock which comprises as a step therein the transfer of thewet ,web on leaving the usual fourdrinier wire to a second wire equippedonly with suction and press means for removing a further moderate amountof the moisture content of the'web before its transfer to the felts.

2. The process of manufacturing paper from highly gelatinized stockwhich comprises as a step therein carrying the wet paper web from theusual forming fourdrinier wire over a second fourdrinier wire equippedwith flat suction boxes and final couch and press rolls for the removalof a further moderate portion of the moisture content of the web priorto transferring it to the felts.

3. The process of manufacturing glassine,

imitation parchment, and like paper which tion parchment and like paperwhich com-.

prises as a step therein impregnating the paper web when partially driedbut still containing a considerable moisture content with an aqueoussolution of materials like cerelose and glycerin adapted to enhance thetransparency, pliability and other desirable features of the paper.

6. The process, of making paper ofthe type described which comprisesimpregnating the paper web when partially dried but still retaining aconsiderable portion of its moisture content with an aqueous solution ofmaterials like cerelose and glycerin adapted to enhance thetransparency, plasticity, and other qualities of the paper andcontrolling the degree of such qualities by varying the water in saidsolution.

. 7. The process ofmanufacturing glassine paper which comprises as astep therein dampening the paper, preparatory to running it through thesupercalenders, with an alkali treated water.

8. The process of manufacturing glassine paper which comprises as a steptherein dampening the paper by running 1t through a mechanical dampenerand then over an atter both in a dampening machine and with an atolmizerand then winding it into a tight rol 10. The process of manufacturingpaper from a highly gelatinized stock which comprises as steps thereinremoving from the Wet paper web a portion of its moisture content afterleaving the first fourdrinier wire and before passing to the felts, andwhile the sheet is being dried impregnating it with a solution ofmaterials like meta-silicate, cerelose and a plasticizer adapted toimprove the transparency, glossiness of surface, silver whiteness, andpliability of the finished paper. v

11. The process of, manufacturing glassine paper which comprises assteps Etherein' impregnating the sheet,while it is being dried with asolution containing materials.

like cerelose and glycerin adapted to improve the transparency, silverwhiteness, glossiness of surface, and pliability of the finished paper,and dampening it preparatory to running it through the supercalenderswith an alkali treated water.

12. The process ofmanufacturing glassine paper which comprises as stepstherein impregnating the sheet while it is being dried with a solutioncontaining materials like cerelose and glycerin adapted to improve thetransparency, silver whiteness, glossiness of surface, and pliability ofthe finished paper, and dampening itpreparatory to running it throughthe supercalenders with an alkali treated water applied to one sidethereof both by a mechanical dampcner and an atomizer, brushing thewater evenly over its surface, and rolling the moistened paper into atight roll.

13. The process of making a supercalendered and waxed paper fromhighlygelatinized stock which comprises as steps there in removingadditional moisture from the wet web after it leaves the fourdrinierwire and before it is transferred to the felts, impregnating the sheetwhile being dried with a solution containing cerelose and glycerin ortheir equivalents, thoroughly and evenly dampening the sheet with analkali treated water preparatory to running it through thesupercalenders, and coating the supercalendered sheet with a hightemperature wax.

14. A paper machine of the type described comprising a secondfourdrinier wire inserted in tandem with the usual fourdrinier wire andbefore the first felt.

15. A paper machine for the manufacture of paper from highly gelatinizedstock having its battery of drying cylinders divided at a point wherethe paper web still retains a considerable portion of its moisturecontent into two sections and intermediate said sections, a pressthrough which the partially dried paper web is carried incontact with afilm of an impregnating solution adapted to enhance the transparency,silver whiteness and plasticity of the paper.

16. A paper machine for the manufacture of a supercalendered paper froma highly gelatinized stock comprising as means for dampening the paperpreparatory to running it through the supercalenders a mechanicaldampener, an atomizer, means for brushing the sprayed water evenly overand intimately in contact with the fibers of the sheet, and means forreeling the sheet into a tight roll.

17. A paper machine for the manufacture of paper from a highlygelatinized stock comprising a second fourdrinier wire in serted intandem with the usual fourdrinier wire and before the first felt and abattery of drying cylinders divided into two sections and between saidsections means for subjecting the partially dried sheet to a bath ofimpregnating solution.

18. A' paper machine for the manufacture of a supercalendered and waxedpaper from a highly gelatinized stock comprising a second fourdrinierwire inserted in tandem with the usual fourdrinier wire and before thefirst felt, a battery of drying cy1-' inders divided into two sectionsand between said sections, means for sub1ecting the partially driedsheet to a bath of an impr egnating' solution; means for cooling thesur-

